Warden: W-band advanced radar for debris early notification form ISS
Battaglia, R. ; Ferri, M. ; Dainelli, V. ; et al. ; - ASI Sponsor
Jan - 2003
DOI: 10.1109/AERO.2003.1235042
ISSN : 1095-323X ; ISBN : 0-7803-7651-X

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type: Conference Proceedings

Abstract
The feasibility of a radar instrument working at 95 GHz placed on ISS (International Space Station) to detect very small debris has been investigated and analyzed in this paper. First of all a study about the debris population around the ISS orbit has been taken under consideration by analyzing the debris flux and by determining the preliminary design and mission parameters for Warden instrument, as for instance the pointing angle of the antenna reflector. A technology survey has been also performed to individuate the state of the art in the millimeter wave frequencies band, with particular reference to the transmitter, the front-end, the master oscillator and for A/D converters and DSPs (Digital Signal Processors) suitable for space. The proposed solution for the ISS on board experiment was basically composed of two segments: the on-orbit segment, that is the payload and the ground segment. The on-orbit segment deals with a radar sensor working at 95 GHz which represents a good trade-off between satisfying the limited power consumption available on ISS ExPA (Express Pallet) adapter and having significant range and detection performance necessary for the success of the overall mission, with particular reference to the scientific results. In the overall radar system design major emphasis has been given mainly to the weights, the overall dimensions, and to the EMC problems due to the simultaneous presence of other experiments on the same ExPA. Once fixed the transmitted power, the pulse length and the probability of detection different performances in range are predicting depending on the dimension of the debris and on the approaching speed. For example a detection range (90\% PD) of about 180 Km is predicted for a debris of 50 cm running at a relative speed of 10 Km/sec (F=95 GHz, 1 m Cassegrain monopulse antenna, 1000W peak power, 40 \musec pulse length, 2.5-100 KHz staggered p.r.f.) Concerning the ground segment, a preliminary architecture has been proposed based upon the extensive use of existing infrastructures and facilities and including a WARDEN control system mainly for all concerns on board payload support, a mission control facility for the general planning of the ground and space resources, and a debris data processing devoted to perform all the- activities relevant to the supply of products and services based on payload according to user request. In conclusion the proposed Warden experiment offers several opportunities both in technological field by giving the possibility to verify the sue of millimeter waves components in space environment helpful for future ESA components qualification plan, and in scientific field to validate the concept of a future stand-alone flying on-orbit space-based radar devoted to the detection of very small debris population (0.5 รท 1 cm as diameter).

keywords : 1000 W,10E3 ms-1,180E3 m,50E-3 m,95 GHz,Analog-to-digital converters,Control systems,DSP,EMC problems,ExPA,ISS,Instruments,International Space Station,Millimeter wave radar,Millimeter wave technology,Payloads,Radar detection,Reflector antennas,Space technology,Spaceborne radar,W-band radar,Warden,aerospace computing,aerospace control,aerospace instrumentation,analogue-digital conversion,antenna reflector,board payload support,components qualification plan,control system,debris data processing,debris early notification,debris flux,debris population,digital signal processing chips,digital signal processors,electromagnetic compatibility,express pallet adapter,ground segment,international space station,millimeter waves components,millimeterwave frequencies band,mission control facility,on board experiment,on-orbit segment,radar detection,radar instrument working,radar sensor,radar signal processing,space environment,space resources,space-based radar,technology survey